1. Field of the Invention
The present invention relates to a combustion device and, particularly, to a safe combustion device.
2. Description of the Related Art
Conventional combustion devices are characterized to two types. A combustion device having no wick(s) is one type, like a fireplace using bioalcohol as fuel, and a combustion device having wick(s) is another type. However, there has always been a problem about the safety of using bioalcohol because it is flammable, and it is difficult to keep the size of the flame in control. Therefore, the combustion devices, which use flammable fuels and have wicks, can be ignited from the wicks rather than from the flammable fuel directly, and the size of the flames is in control. Generally, the combustion device, which has a wick, includes a plate, and the wick is disposed on the plate and has an end dangled into a reservoir for the fuel. The plate is resistant to heat. The wick is generally made up of cotton fibers. For instance, an alcohol burner includes a container in which the alcohol fuel is stored and a wick having one end disposed outside the container and another end soaked into the alcohol fuel. The wick can draw the fuel by capillary action up into the flame. In addition, the container is enclosed.
U.S. Pat. No. 6,960,320 protects an oil burning lamp. The oil burning lamp includes an enclosed reservoir. A wick is disposed in the reservoir and includes an end soaked in and another end disposed outside the fuel. A shade surrounds the wick to avoid outside air blowing onto the wick and putting out the flame. The shade has an opening, and its effect on safeguarding the wick against the outside air is decreased when the opening is too big. The shade, however, causes poor heat dissipation and obstructs a supply of the outside air if the opening is too small. Moreover, poor heat dissipation causes the temperature of the shield to become too hot to touch safely, and a lack of sufficient outside air causes an incomplete combustion and creates black and poisonous smoke. Moreover, because of the poor air ventilation, the heat emitted by the oil burning lamp and the heat dissipation is not in balance, with the longer use time of the oil burning lamp the higher temperature it will get.
In addition, nonflammable fuel and flammable fuel have different flash points. Nonflammable fuel has higher flash points than flammable fuel. It is harder to ignite nonflammable fuel than flammable fuel. However, if the temperature of the oil burning lamp is higher than the flash points of nonflammable fuel, nonflammable fuel can vaporize easily like flammable fuel and is at a higher risk of backdraft and flashover. Accordingly, the size of the flame created by the oil burning lamp is generally small, in order to prevent the oil burning lamp from getting hotter than the flash point of fuel.
The present invention is, therefore, intended to obviate or at least alleviate the problems encountered in the prior art.